Modern Internally Geared Hubs

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on July 6, 2011 at 12:38pm

I have a SA front brake hub (X-FDD) and really like how it stops up front.  The built-in dyno is really nice too.  When/if my SRAM S7 ever dies I'll be buying a SA rear hub to match it with a drum brake built in.   I'm not 100% happy with the S7 and wish it had a brake built in.  I'm even thinking of trying an older AW hub with built in brake as I really like the old Sturmey Hubs.  The SRAM doesn't hold a candle to the older 3-speed hubs with regard to anything but having more gears (300% gear ratio is nice though.)

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on July 6, 2011 at 1:22pm

I only went with the S7 because I got it really cheap used from someone on bikeforums.net

 

In the future I am pretty sure I'd go with a Sturmey-Archer. 

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Permalink Reply by Mike Bullis 5.5-6.5 miles on July 6, 2011 at 7:59pm

I've got a similar set up, X-FDD and S7 but I managed to score an S7 with a drum brake. The S7 is a good hub, just not a great one. It has performed much better, though, since I drilled and tapped a hole in the hub shell for an oil filler and run Mobil1 in it instead of grease.

 

I agree with Mr. Baum, though, can't hold a candle to a broken in 3 speed hub.

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on July 6, 2011 at 8:08pm

I am interested in this grease -> oil modification.   I've never heard of it.  You have piqued my interest!

 

Is there a mod page somewhere that details this?  I've got a baggie full of new SA oil ports that I use whenever I overhaul any SA hub (I  never re-use an older plastic one or even a metal one as they leak.)  Is there a specific location to drill the S7?  I might not want to do this right away but I'd love to research it and think about it.  I would imagine that cold-weather performance would be much improved with an oil bath rather than a grease pack. 

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Permalink Reply by Allen Wrench on July 6, 2011 at 11:00pm

Look at John Allen's hub pages and what's left of Hubstripping for the oil mods. SA (and Sachs) used oil and (rather porous) seals on the old hubs, but (except for Rohloff and Shimano 11-speed) everything else uses (special, expensive) grease. Oil lubricates better if you can keep it in there, the argument goes. It's a little like hearing the difference between a regular tweeter and a beryllium audiophile one - if you can feel the difference between a grease filled hub and an oil filled one you should watch out for peas under your mattress. Still, the grease needs changing every couple of years and the oil is easy to refill.  I've never tried it. But Phil tenacious oil in a SA shifts slower than SA oil, so maybe it makes a difference.

 

Roller brakes, the newer ones, are pretty good for back brakes but they overheat (I hear) and don't stop well (I know) on the front. The old ones are better than wet 10-speed brakes, barely. The new ones are OK, but cantilevers or V-brakes are much better except in winter. I have had a few bikes with roller brakes. They are fine in winter, summer, rain, dry... It's flat here though.

 

The SA drum brakes are supposed to be good; a guy who builds a lot of bikes in Boston likes them a lot but recommends the larger ones (they come in two diameters). There's also a SA dynamo drum brake hub that always looks interesting. A few people have told me that for heavy loads on hills you are better with a disc brake (preferably hydraulic - not sure exactly how much benefit that adds).

 

I have a mixed opinion of the Nexus 8 hubs but I'm probably abusing them with too much load. (we run them carrying about 400 lbs every day and sometimes more on cargo bikes) Not bad, plenty of speeds, a little irritating that some speeds are closer to each other than others. We had one fail and it's a pain to fix here. We had to buy a new wheel. Nice enough when they work. Much much nicer than the SA 5-speed of old. May need regreasing or they fail after 2 years - there are some discussions online (in England mostly) about early deaths of Nexus 8 hubs.

 

You don't need many speeds nor much range in Chicago though so maybe the SA AW is the way to go here. If you want to try something different consider the new NuVinci which has infinitely variable speeds - no brake though. Or just sell your car and get a Rohloff - who cares how it rides or brakes - it's the most expensive bike part ever! How can you go wrong?

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Permalink Reply by Mike Bullis 5.5-6.5 miles on July 7, 2011 at 5:27am

One of the nicer things about the S7 with a drum brake is that it has an aluminum shell.

I had mine apart for a shifting issue(That's a whole 'nother story)that was the result of the 'special grease' not being able to migrate to the very center of the hub axle where the thrust keys are located. Unheated garage=moisture=rust. Anywho, while I had the guts out and soaking, I took a gander in the hub shell and picked a spot between the bearing races and where my drill fit between the spokes and had at it. Threaded the hole M6 and I was done.

I did the SA method of heavy bearing grease to seal the hub(seems to be working)and use Mobil1 as a lube. The hub is much quieter and shifts a hell of a lot better. I'll try to get some pics up this weekend.
James Baum said:

I am interested in this grease -> oil modification.   I've never heard of it.  You have piqued my interest!

 

Is there a mod page somewhere that details this?  I've got a baggie full of new SA oil ports that I use whenever I overhaul any SA hub (I  never re-use an older plastic one or even a metal one as they leak.)  Is there a specific location to drill the S7?  I might not want to do this right away but I'd love to research it and think about it.  I would imagine that cold-weather performance would be much improved with an oil bath rather than a grease pack. 

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on July 7, 2011 at 6:43am

It's too bad that the hub-specific greases are so expensive.  I've had good luck using common SGLI#2 lithium variants (both disk brake and non wheel-bearing greases) in the old Shimano 3-speed hubs.

 

My S7 also has an aluminum shell rather than the steel one.  It almost looks like the brake hub without the brake. Perhaps it is an early model.  I've often wondered if it were possible to convert it to a brake hub if only I could find the brakey bits.

 

I'll have to check into the hubstripping site for that mod.  There used to be a lot of good info in there.  I've got a Bendix yellow-band kickback hub that I need to tear into as it sounds like a margarita machine in second gear.  I'm sure there is something wrong in there but hope springs eternal and i'm hoping it is just because of old grease and rusty bearings.  If parts are needed that are unobtanium I am going to be bummed. I've only just laced it up and tried to put into service.  The hubstripping site has good info on tearing it apart and how to build the bendix cone tool out of a 3/8" pipe.

 

I also know someone with a Sachs Automatic 2-speed coaster who won't let me take it apart as it seems to be running fine.  Oh, how I want to take that hub apart and see with my own fingers what makes it tick.  Old manual PDF scans just don't do it for me like poking my hands into the innards. 

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Permalink Reply by Doug Haynes on July 7, 2011 at 10:24am

I would be interested ion some pics/details of this mod because I feel my X-RD3 could benefit from a similar mod...

Mike Bullis said:

I've got a similar set up, X-FDD and S7 but I managed to score an S7 with a drum brake. The S7 is a good hub, just not a great one. It has performed much better, though, since I drilled and tapped a hole in the hub shell for an oil filler and run Mobil1 in it instead of grease.

 

I agree with Mr. Baum, though, can't hold a candle to a broken in 3 speed hub.

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Permalink Reply by Doug Haynes on July 7, 2011 at 10:30am

I have a bike set up with a front drum/dyno and rear 3spd/drum if you want to actually get a good feel for how they ride. I have run this set up for a bit over a year, I think, and rode all winter on them and have had no real issues beyond the rear getting a little loud recently but I think that is mostly a lubrication issue.  Actual performance has been spot on, no issues with the exception of a really bizarre failure when a plastic bag blew into the wheel, wrapped around the hub and popped the snap ring and cog off but that was hardly the hubs fault.

 

I like them better than the roller brake but have not ridden those beyond short test ride but I think they are about the same when it comes to effectiveness. 

 

 

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Permalink Reply by Far'arned Retrogrumpalunkus #63 on July 7, 2011 at 10:43am

I feel that on a light bike 3 speeds would be plenty in this flatland.

 

It is only when one starts to lay on the load on a heavy bike that more gears are nice.  Being able to start out on a really low gear from starts is nice.  But with the close ratios of the AW and similar 3-speeds  to make the low gear low enough to really make starting off easier the higher gears would be too low as well.  Something like the 300%+ ratio range of the modern 7-8 speeds is more appreciated between the lowest gears and the higher ones -even if the middle gears were larger jumps.  If the AW could be re-designed so that 3 gears would give 200-250% spread between high and low with 2nd somewhere in between it might almost make it usable.  But with 2nd gear being direct drive and 1st being only -25% and 3rd being +33-1/3% that doesn't really spread it out enough for a really heavy/loaded bike.  

 

For just bombing around town with a light load my Sports with the AW on it is about perfect.  Hauling a heavy load of groceries or crap from menards th S7 on my Big Dumb Ross MTB is appreciated as I can use gears all the way between 30-ish gear/inch to 90-ish.  That really comes in handy.  I'm thinking of gearing it down even lower to go between 25-ish to 75-ish

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Permalink Reply by Steven Vance on July 7, 2011 at 1:41pm

Read up on Bakfiets en Meer ("Box bikes and more"). 

Bakfiets en Meer

 

The owner of WorkCycles writes often about these things, which are integral to Dutch bikes. 

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Permalink Reply by Mike Bullis 5.5-6.5 miles on July 7, 2011 at 7:08pm

I've had some luck converting an SA S3C from coaster to AW. Don't know how going the other way on a Sram would work.

 

On the Bendix kickback hubs, if you can get them into second, that's a good sign. Usually, the spring(I think its called the 'overrunning clutch spring')weakens and won't allow the hub to shift. The noise could be dried grease(good)bad bearings(kinda good)or a bum planetary gear(kinda bad)or gear ring(eep!). I have some kickback parts in my stash.

I prefer the old manually shifted Bendix 2 speeds to the kickbacks. Extremely simple, wide range, and easily converted to 2 speed fixed gear. http://www.flickr.com/photos/21499296@N08/sets/72157622894296310/

 

The F&S Automatic is on my wish list of cool hubs to have. Don't know if I'll ever get lucky.

 

Probably should stop hijacking this thread.8-)

 

James Baum said:

 

 

My S7 also has an aluminum shell rather than the steel one.  It almost looks like the brake hub without the brake. Perhaps it is an early model.  I've often wondered if it were possible to convert it to a brake hub if only I could find the brakey bits.

 

 

I'll have to check into the hubstripping site for that mod.  There used to be a lot of good info in there.  I've got a Bendix yellow-band kickback hub that I need to tear into as it sounds like a margarita machine in second gear.  I'm sure there is something wrong in there but hope springs eternal and i'm hoping it is just because of old grease and rusty bearings.  If parts are needed that are unobtanium I am going to be bummed. I've only just laced it up and tried to put into service.  The hubstripping site has good info on tearing it apart and how to build the bendix cone tool out of a 3/8" pipe.

 

I also know someone with a Sachs Automatic 2-speed coaster who won't let me take it apart as it seems to be running fine.  Oh, how I want to take that hub apart and see with my own fingers what makes it tick.  Old manual PDF scans just don't do it for me like poking my hands into the innards. 

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